Surah An-Nas  (The Mankind)
In the Name of Allah, the Most Gracious, the Most Merciful.
1. "Say: 'I seek refuge with the Lord of mankind"
2. "The King of mankind"
3. "The God of mankind"
(1-3) This Surah describes three Attributes of Allah the All-Mighty. He gives sustenance to mankind, He is Sovereign and He is Worthy of worship. All things are created by Him, possessed by Him, and subservient to Him. He commands anyone who wants refuge to seek in it the Lord who has these Attributes.
4. "From the evil of the whisperer"
(4) Satan entices people to commit sins as he makes evil attractive to men. Only Allah can grant protection from the evil of Satan. According to a Hadith, the Prophet said, "With everyone of you there is a devil." The Companions asked, "Is there a devil even with you?" The Prophet said, "Yes, but Allah has granted me protection against him."
Al-Bukhari and Muslim report that once when the Prophet was in seclusion (i'tikaf) in the mosque, his wife Safiyyah went to see him. When she left, the Prophet accompanied her to his house. On the way he met two Companions from Ansar who were passing by. They sped up their pace when they saw him. He called them and said, "This is my wife Safiyyah bint Huyay." They said, "Subhanallah! O Messenger of Allah, why are you saying this?" The Prophet said, "Satan flows inside man like blood. I feared, may be he put bad thoughts about me in your minds."
Al-Hafidh Abu Ya'la Musily quoted a Hadith which reported the Prophet as saying:
"Satan puts his hand on the heart of man. If he celebrates the remembrance of Allah he removes his hand and if he forgets Allah, Satan overcomes his heart fully. This is the 'evil of the whisperer.' "
Ahmad ibn Hanbal reported a Hadith: The Prophet was once riding a mule and a Companion was riding behind him on it. The mule stumbled. The Companion spontaneously uttered, "May Satan perish." The Prophet says, "Do not say that. It encourages Satan," and he said, "I knocked him with my strength. But if you say, 'In the name of Allah' he is dwarfed and becomes like a fly." This proves that the remembrance of Allah helps overcome Satan while leaving it augments his power.
Ibn 'Abbas, says that the Satan is lying in wait for man. When he forgets Allah, he starts whispering, and when he begins the remembrance of Allah, he retreats.
Sulayman said: "I am told that in happiness and sorrow Satan bores into the heart of man, i.e., he deludes him. If man remembers Allah, he flees away." Ibn 'Abbas, also says that Satan preaches evil and when man obeys him, he leaves him.
5. "Who whispers in the breasts of mankind"
6. "Of jinn and men."
(5,6) The expression "Who whispers in the breasts of mankind" may be interpreted in two ways. One interpretation is that Satan whispers in the chests of people belonging to the human race or the race of jinn. The other interpretation is that the devils from among the human race and the jinn whisper in the chests of other people. At another place Allah says:
"And so We appointed for every Prophet an enemy - devils among mankind and jinn, inspiring one another with adorned speech as a delusion ... "
Abu Dharr reported that once he went to the mosque and sat with the Prophet. He asked me, "Did you pray?" When I said no, he said, "Offer two rak'ah." When I again sat after finishing the prayer, he said, "Abu Dharr, seek refuge against the devils among men and jinn." I asked, "Are there devils among men also?" He said, "Yes." I asked him, "O Messenger of Allah, which is the greatest verse in the Qur'an?" He said, "The Verse of the Throne - (2:255)." [Imam Ahmad. This Hadith has also been reported by Nasa'i, Abu Hatim and others]
From Tafsir Ibn Kathir (abridged). Translation by Habib Badr.